Technical Field
The present disclosure relates to a vehicle body transformable front section structure.
Related Art
Japanese Patent Application Laid-Open (JP-A) No. 2009-067066 describes an disclosure relating to a shock absorbing device. The shock absorbing device is provided with a gas generator that is housed in an internal space of a crash box, and configuration is made in which the gas generator is actuated when an acceleration sensor installed to the vehicle has detected an acceleration of a threshold value or greater. Thus, when collision load from a vehicle front side is input, in cases in which the acceleration sensor has detected acceleration of the threshold value or greater, high pressure gas generated by the gas generator is supplied to the internal space of the crash box, thereby raising the strength of the crash box. However, in cases in which the acceleration sensor has detected an acceleration smaller than the threshold value, the gas generator is not actuated, and there is no change in the strength of the crash box.
Accordingly, the related art described in JP-A No. 2009-067066 is capable of accommodating a wide range of collision conditions by varying the strength of the crash box according to the magnitude of the collision during an actual collision.
However, in the case of the related art described in JP-A No. 2009-067066, since the high pressure gas is supplied into the internal space of the crash box following input of the collision load to the vehicle, it is conceivable that deformation could occur before the strength of the crash box has been completely raised by the high pressure gas. Moreover, even if the acceleration detected by the acceleration sensor is a value close to the threshold value, so long as the detected acceleration is smaller than the threshold value, the gas generator will not actuate, and so it is conceivable that the amount of deformation in the crash box could be insufficient to absorb the collision load. Namely, in the related art described in JP-A No. 2009-067066, there is room for improvement regarding the point of improving absorption performance of collision load from the vehicle front side.
In consideration of the above, a configuration is conceivable in which mountain portions and valley portions are provided alternately to the crash box along a vehicle front-rear direction such that the crash box is configured capable of extending along the vehicle front-rear direction, and thus, when a vehicle frontal collision is predicted, the crash box is extended using the gas generator. In such a configuration, a crushing stroke over which collision load can be absorbed from the vehicle front side is lengthened, and collision load from the vehicle front side can be absorbed accommodating collision loads of different magnitudes according to the size of the crush amount of the crash box.
However, it is conceivable that if collision load from the vehicle front side were to be input in a state in which the crash box has not extended to a sufficiently complete state, namely, a state in which crease lines remained, the crash box could fold and deform along the alternately provided mountain portions and valley portions, and sufficient energy absorption performance could become unobtainable. Namely, even when a crash box is configured capable of extending in the vehicle front-rear direction, an issue remains regarding the point of suppressing crease lines from remaining, and stably absorbing collision load, in a state in which the crash box has extended.